atac2.cpp: In function 'int main()': atac2.cpp:19: warning: operation on 'st' may be undefined atac2.cpp:20: warning: operation on 'dr' may be undefined atac2.cpp:20: warning: operation on 'dr' may be undefined atac2.cpp:10: warning: unused variable 'j' atac2.cpp:10: warning: unused variable 'y' atac2.cpp:7: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result atac2.cpp:8: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result atac2.cpp:12: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result atac2.cpp:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result